Autonomous Self‐Assembly of Ionic Nanoparticles into Hexagonally Close‐Packed Lattices at a Planar Oil–Water Interface

Sashuk, Volodymyr; Hołyst, Robert; Wojciechowski, Tomasz; Górecka, Ewa; Fiałkowski, Marcin

doi:10.1002/chem.201103272

Cited by 10 publications

(10 citation statements)

References 45 publications

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“…addition of ethanol or methanol to the interfacial region, 23,29,30 precise injection of colloidal AuNP solutions prepared in methanol at water-organic solvent interfaces, 31 use of salts, 32 solvent evaporation, 33 covalent bonding 14,34,35 and self-assembly provided by electrostatic interactions. [36][37][38] Applications of these self-assembled nanofilms include filters, mirrors 5,39 or smart mirrors, 40 substrates for Surface Enhanced Raman Spectroscopy (SERS) sensors, [41][42][43][44] and as a method to enhance non-linear Second Harmonic Generation (SHG) optical responses. [45][46][47] Finally, these nanofilms were used to achieve electrocatalysis at electrically polarized liquid-liquid interfaces.…”

Section: Introductionmentioning

confidence: 99%

Self-healing gold mirrors and filters at liquid–liquid interfaces

et al. 2016

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The optical and morphological properties of lustrous metal self-healing liquid-like nanofilms were systematically studied for different applications (e.g., optical mirrors or filters). These nanofilms were formed by a one-step self-assembly methodology of gold nanoparticles (AuNPs) at immiscible water-oil interfaces, previously reported by our group. We investigated a host of experimental variables and herein report their influence on the optical properties of nanofilms: AuNP mean diameter, interfacial AuNP surface coverage, nature of the organic solvent, and nature of the lipophilic organic molecule that caps the AuNPs in the interfacial nanofilm. To probe the interfacial gold nanofilms we used in situ (UV-vis-NIR spectroscopy and optical microscopy) as well as ex situ (SEM and TEM of interfacial gold nanofilms transferred to silicon substrates) techniques. The interfacial AuNP surface coverage strongly influenced the morphology of the interfacial nanofilms, and in turn their maximum reflectance and absorbance. We observed three distinct morphological regimes; (i) smooth 2D monolayers of "floating islands" of AuNPs at low surface coverages, (ii) a mixed 2D/3D regime with the beginnings of 3D nanostructures consisting of small piles of adsorbed AuNPs even under sub-full-monolayer conditions and, finally, (iii) a 3D regime characterised by the 2D full-monolayer being covered in significant piles of adsorbed AuNPs. A maximal value of reflectance reached 58% in comparison with a solid gold mirror, when 38 nm mean diameter AuNPs were used at a water-nitrobenzene interface. Meanwhile, interfacial gold nanofilms prepared with 12 nm mean diameter AuNPs exhibited the highest extinction intensities at ca. 690 nm and absorbance around 90% of the incident light, making them an attractive candidate for filtering applications. Furthermore, the interparticle spacing, and resulting interparticle plasmon coupling derived optical properties, varied significantly on replacing tetrathiafulvalene with neocuproine as the AuNP capping ligand in the nanofilm. These interfacial nanofilms formed with neocuproine and 38 nm mean diameter AuNPs, at monolayer surface coverages and above, were black due to aggregation and broadband absorbance.

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Section: Introductionmentioning

confidence: 99%

Self-healing gold mirrors and filters at liquid–liquid interfaces

et al. 2016

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“…Silicon wafers were purchased from ITME (Warsaw). Hydrophobic glass vials were prepared by soaking vials in a TDS solution …”

Section: Methodsmentioning

confidence: 99%

Submicron Colloidosomes of Tunable Size and Wall Thickness

2017

Self Cite

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We present a simple method for the fabrication of colloidal capsules of different sizes ranging from below 100 nm up to one micron. The capsules are produced by self-assembling 5 nm gold nanoparticles at the interface of oil-in-water emulsion droplets. The size of the capsules is regulated by tuning the wetting properties of the nanoparticles by changing either the composition of their ligand shell or the composition of the oil phase. The modified wettability affects not only the size but also the thickness of capsule walls. The wall can be thin if it is made of a single layer of the nanoparticles or thick when composed of multilayers. The durability of such capsules is quite high, although it can be improved by chemical cross-linking with UV light. Such capsules have low permeability, so they can store a molecular cargo and then release it on demand.

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“…These distinct spacings between the gold cores are clearly caused by the polymer brushes, since no other substances are present in the solution. An electrostatic effect [77] can be excluded, because pNIPAm-coated AuNPs are completely uncharged, as shown by zeta potential measurements.…”

Section: Grafting Of Polymers With Single Trithiocarbonate Groups To mentioning

confidence: 97%

Nanohybrids of Gold Particles

Ebeling

2015

Springer Theses

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The design and the characterization of the substrate components for this chapter, gold nanocrystals from the ex-situ two-phase Brust-Schiffrin synthesis and from reduction with citrate ions ci Au ν-3 , were described in Section 5.1. In the following, it will be outlined how these AuNPs can be functionalized with non-polymeric ligands of different types for stabilization and introduction of functional groups, especially hydroxyl and azido moieties, to which RAFT agents with complementary functionalities could then be coupled, and how they can be coated with the NIPAm RAFT polymers prepared in Section 5.4. Hereby, the binding motifs of ligands bearing trithiocarbonate groups will be the particular focus. Different ligands on AuNPs Functionalization of Brust-Schiffrin gold nanocrystalsAuNPs prepared by the ex-situ two-phase Brust-Schiffrin method were presented and their ligand-independent properties were characterized in Section 5.1.3.3 (also see Table 5.2, Section 5.1.5). These nanocrystals are very well suited for functionalization reactions for three major reasons:• The weakly bound tetraoctylammonium bromide is readily replaced by all ligands that form stronger bonds to the gold surface.• The sodium borohydride can be completely washed off prior to the addition of the ligand, so that even very reduction-sensitive molecules can be used.• The arising particle size and shape characteristics are independent of the employed ligand, enabling comparative experiments with different functionalization agents.

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Autonomous Self‐Assembly of Ionic Nanoparticles into Hexagonally Close‐Packed Lattices at a Planar Oil–Water Interface

Abstract: Let's get charged! Positively charged nanoparticles (NPs) spontaneously self-assemble into hexagonally close-packed lattices at a planar CH(2)Cl(2)-water interface. The self-assembly process is fully autonomous and occurs without any external manipulation.

Cited by 10 publications

References 45 publications

Self-healing gold mirrors and filters at liquid–liquid interfaces

Self-healing gold mirrors and filters at liquid–liquid interfaces

Submicron Colloidosomes of Tunable Size and Wall Thickness

Nanohybrids of Gold Particles

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